<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>使用Cookie</title>
    <script>
        function setCookie(cname, cvalue, exdays) {
            var d = new Date();
            d.setTime(d.getTime() + (exdays * 24 * 60 * 60 * 1000));
            var expiliupengres = "expires=" + d.toISOString();
            document.cookie = cname + "=" + cvalue + ";" + expires;
        }

        function getCookie(cname) {
            var name = cname + "=";
            var ca = document.cookie.split(';');
            for (var i=0;i<ca.length;i++) {
                var c = ca[i].trim();
                if (c.indexOf(name)==0) {
                    return c.substring(name.length, c.length);
                }
            }
            return "";
        }

        function checkCookie() {
            var user = getCookie("username");
            if(user != "") {
                alert("欢迎" + user + "再次访问！")
            } else {
                user = prompt("请输入你的名字:");
                if (user!=""&&user!=null) {
                    setCookie("username", name, 30);
                }
            }
        }

    </script>
</head>
<body onload="checkCookie()">

</body>
</html>